Hey guys, first time posting here.
Android Messages and MightyText are both Android apps that can be synced to devices running Windows so you can text without using your phone. In order to sync, they utilize some sort of pop-up in your browser. Google Sign-In also uses a pop-up in order to function properly. I’m no expert on how this kind of coding stuff works, but none of these 3 sites work on Brave but they function just fine on Chrome, so I’m assuming something in Brave’s settings is blocking the pop-ups from functioning properly. Does anyone know how to fix this? I’ve provided screenshots of the error messages I get on each site.

Hi @weave!
These are fairly common errors and they have to do with the way your Brave Shields are configured.
I am able to pair with Android Messages and enable pop-up auth/2FA for Google with the following settings:

ALSO: Take note of where it is that you are changing these settings. If you click the lion Icon in the top right (as displayed in the picture above) and open the drop down panel, these settings are site-specific, meaning that the settings in that panel will only apply to the website currently in focus. So when adjust your settings for the Android Messages website and get it to work, you’ll have to readjust them for the remaining websites where you get that behavior.

I hope this helps! Please let me know if you have any further questions!